Antioxidant activity and enzymes inhibitory properties of several extracts from two Moroccan Asteraceae species

The present work reports investigation on phenolic compounds, antioxidant activity and enzyme inhibitory activities (acetylcholinesterase, butyrylcholinesterase, tyrosinase, α-amylase and α-glucosidase) of different extracts from two Moroccan Asteraceae species; Bubonium imbricatum Cav. and Cladanthus arabicus (L.) Cass. B. imbricatum extracts contained the highest amounts of phenolics and flavonoids, and also exhibited higher antioxidant activity. In this species, the highest total phenolic (1611.13 ± 14.23 μmolGAE/gextract) and flavonoid (376.11 ± 8.22 μmolQE/gextract) contents were observed in aqueous-methanol extract obtained by maceration. Further, UHPLC-MS analysis of C. arabicus and B. imbricatum extracts revealed the presence of several flavonoids (diosmetin, luteolin, apigenin 7-glucoside, and apigenin) and phenolic acids (benzoic, protocatechuic, p-coumaric, gallic, vanillic, caffeic, ferulic and isochlorogenic acids). The antioxidant activity of the extracts was dependent of the extraction process and solvent used. Aqueous-methanol extract of B. imbricatum prepared by maceration showed the highest activity with DPPH, ABTS and FRAP tests (respectively: IC50 = 8.53 ± 0.38 μg/ml, 3461.8 ± 9.38 μmolTE/gextract and 3281.6 ± 47.43 μmolAAE/gextract). The results indicated that most of the tested extracts or essential oils exhibited activity towards the tested enzymes. Overall, the results obtained in this work indicated the two Moroccan species studied, particularly B. imbricatum, as valuable sources of natural agents beneficial for human health.